Valve, milking claw and milking system

ABSTRACT

A diaphragm valve for shutting off milk flow through a claw ( 13 ) of a vacuum driven milking machine has, in a preferred embodiment, a lever ( 5 ) linked ( 6 ), outside the milk flow, to the diaphragm ( 4 ), thereby avoiding any bushings which are prone to leakage. The lever ( 5 ) can be swung manually to a position holding the diaphragm away from its seat thereby permitting milk flow. In the automatically closing embodiments, the lever is swung in this case against the bias of a spring ( 7 ) and is retained in this open position if the suction force acting on the diaphragm ( 4 ) and the link ( 6 ) is sufficient to overcome the bias of the spring ( 7 ), which will be the case when there is normal milk flow through the valve. Upon detachment of the tea from the animal&#39;s teat only air will flow through the valve, thereby reducing the suction force exerted on the link ( 6 ) and allowing the spring ( 7 ) to swing the lever away from its valve-open position to a diaphragm-release position where the air suction will pull the diaphragm to seal against its seat and cut off potentially contaminating air-flow through the system. This inventive principle can, for example, also be embodied in a rotary knob ( 21 ) linked to the diaphragm ( 4 ) and interacting with indined grooves ( 23 ) and springs ( 24 ) biasing the knob to advance to a diaphragm-release position when there is insufficient milk flow. Such a system is particularly useful in sheep or goat dairies where there is frequent attachment and detachment of the clusters.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to a milking claw incorporatinga novel valve design suitable for use in a milking machine as well as toa milking system incorporating suitably a plurality of such valves.

BACKGROUND ART

In known suction actuated milking systems, use has been made of a claw,providing a confluence for the milk flowing in from all the teatcups ofthe cluster, two teatcups in the case of equipment for milking goats orsheep and four teatcups for milking cows. The milk flows from the clawto a milk-receiving vessel. It has been found advantageous to provide ameans to shut off the flow of air through the valve when the teatcupsare removed from or fall off the teats, or prior to removal of theteatcups from the teats. This can be accomplished both manually andautomatically. Known claw valves generally used for this purpose utilizea central shaft provided with a knob outside the valve body for manualoperation, and a conical element sealing against a valve seat in itsclosed position. One such valve is shown and described in GB-B 881 282.This valve, with its through-shaft extending from the flow chamber tothe outside air, has been prone to leakage, allowing impurities to bedrawn into the system. The pulling and pushing of the knob necessary toopen or close the valve requires the use of two hands and can haveergonomic disadvantages when repeated many times.

After removal of the teatcup, this known valve is designed toautomatically shut off when air flows, at an elevated flow rate, throughthe valve from the teatcup, as a result of the dynamic force of therapidly moving air on the bottom of the valve element, and reducedcounterpressure on the other side of the element. Unfortunately, thevalve may also unintentionally close if there is a very high rate ofmilk flow, which is clearly disadvantageous.

OBJECT OF THE INVENTION

The object of the present invention is thus to provide a milking clawand a milking system incorporating such claws, which do not have thesedisadvantages, in a simple, reliable and easily operated design having acompletely sealed of chamber with no penetrating elements.

SUMMARY OF THE INVENTION

The present invention fulfills these and other objects by providing amilking claw valve for shutting off and turning on vacuum-induced flowfrom a teatcup or teatcups in a milking machine, said valve including: avalve body having at least one inlet for milk flow from a teatcup and anoutlet for milk flow from said valve, as well as a valve seat, adiaphragm mounted in said valve body said diaphragm being movablebetween an open position permitting flow from said inlet(s) to saidoutlet, and a closed position sealing against said valve seat, cuttingoff flow between said inlet(s) and said outlet, a manual actuatormounted in or on said valve body to swing or rotate between at leastfirst and second positions, a non-extendible link connected between saidmanual actuator and a point on said diaphragm; the diaphragm being heldin its open position by means of said link when said manual actuator isin its first position; the diaphragm being released to allow it toassume its closed position, when said manual actuator is moved to itssecond position; said diaphragm, when in its open position, exerting viathe link a force on the manual actuator, urging it towards its firstposition.

According to a preferred embodiment of the present invention the manualactuator, which, for example, can be a lever or rotatable knob is biasedtowards its second position; said diaphragm, when in its open position,exerting via the link an opposing force on the manual actuator, urgingit towards its first position; said opposing force, when there is apredetermined suction which induces liquid flow through the valve body,overcoming the biasing force urging the actuator towards its secondposition; said opposing force not overcoming the biasing force whenthere is a drop below said predetermined suction for the liquid flowthrough the valve.

This provides for automatic closing without the disadvantages ofinadvertent closing.

The present invention also encompasses a claw comprising a valveaccording to the invention, and a milking system comprising: a vacuumsource, a milk receiving container, at least one cluster having a clawaccording to the invention and at least two teatcups.

DRAWING SUMMARY

The invention will now be described with reference to a non-limitingexample shown in the accompanying drawings of which:

FIG. 1 shows schematically a milking system according to the invention.

FIG. 2 shows purely schematically a first embodiment of a valveaccording to the invention in its open position.

FIG. 3 shows purely schematically a detail of the same valve in itsclosed position.

FIG. 4 shows purely schematically a second embodiment of a valveaccording to the invention in its closed position.

FIGS. 5(a) and 5(b) show schematically the spring and pin in FIG. 4 in avalve releasing position and in a valve-closed position respectively.

FIGS. 6 and 7 show schematically the open and closed positionsrespectively of an embodiment of the invention similar to that describedin connection with FIGS. 2 and 3, but without any biasing spring.

FIG. 8 shows an embodiment in its closed position intended for manualoperation corresponding to that described in connection with FIG. 4, butwithout any biasing spring.

DETAILED DESCRIPTION

FIG. 1 shows schematically one example of a milking system in accordancewith the present invention, in this case a system for milking sheep. Anumber of milking stations, of which only one is shown here, are drivenby a common vacuum pump 10. Two teatcups 11 are attached to the sheep'steats, which are milked in a well-known manner by a pulsating vacuumprovided through short and long pulse tubes 14 and 15, respectively.Short milk tubes 12 lead from the teatcups 11 to the inventive valvecontained in the claw 13, and from said valve, the milk flows out of theclaw via the long milk tube 19 to a receiving tank 17.

FIG. 2 shows very schematically a first embodiment of the valve 1according to the invention, which can be housed in the claw 13 shown inFIG. 1. The inlet 2 of the valve conducts milk flow coming from thetubes 12 into the valve, and, when the valve is in the open positionshown in FIG. 1, out through the outlet 3 to the tube 19 and the tank 17as shown in FIG. 1. A diaphragm (4) of flexible elastic material isdisposed, when it is in the open position shown in FIG. 2, to permit,without any leakage, flow between the inlet 2 and the outlet 3 in thedirection of the arrow A. When the diaphragm is in the closed positionshown in FIG. 3, it seals against a seat covering both the inlet tube 2and the outlet tube 3 and cuts off the flow of milk and/or air into theoutlet tube 3.

The diaphragm is held in the open position shown in FIG. 2, against thesuction drawing the milk through the valve by a link 6 attached to theportion of the diaphragm above the outflow. The link 6 may be flexible,but is non-extensible. The other end of the link 6 is attached to alever 5, which is pivotally mounted about a pivot point 8 in the valvebody 1. When the lever is in its right-hand end position shown in FIG. 2resting against an abutment in the valve body, the membrane is held upin its open position. When the lever 5 is pivoted to its left-hand endposition shown in FIG. 3, the diaphragm is released, and if there is anysuction in the outlet tube 3, the diaphragm will then close the valve,as shown in FIG. 3. It is possible to switch this lever manually or inthe manner which will be described in the next paragraph.

The lever is biased by a spring 7, in this case a leaf spring, to assumethe position shown in FIG. 3, i.e. the closed position. When there issufficient suction force on the membrane, in this case when milk isdrawn through the valve, a tensile force will be exerted on the link 6,thereby exerting a force on the lever, in its open position shown inFIG. 2, which counteracts the force of the leaf spring 7. Thus, as longas there is suction and the milk is flowing through the valve, the leverwill be held in its open position shown in FIG. 2, unless it is movedmanually to its other position. Should there be a drop in the suctionforce acting on the portion of the diaphragm to which the link 6 isattached, then the leaf spring 7 will be able to flip the lever over tothe position shown in FIG. 3. This drop in suction force will occur ifthe teatcup is removed, either intentionally or by being kicked off bythe animal from the animal's teat and air instead of milk begins to bedrawn through the valve. The vacuum, now drawing air, will cause thediaphragm to seal against the seat as shown in FIG. 3. This will preventany dirt or straw from being drawn into the system. It will also preventvariations in the general vacuum level in the system when moving acluster from one animal to another. This is particularly advantageous insheep and goat dairies where the clusters are moved more frequently thanin cow or buffalo dairies.

A second embodiment of a valve according to the invention is illustratedschematically in FIG. 4. Parts having counterparts in the previouslydescribed embodiment have been given the same reference numerals. Inthis case the schematically shown valve body 20 is round and has one ormore inlets 2 and an outlet 3 as well as a diaphragm 4, which is shownin this case in its closed position sealing against the seat and therebycutting off milk flow between inlet and outlet

A swivel link 6 connects the outlet side of the diaphragm 4 with arotary knob 21 which is rotatably mounted on the round portion of thevalve body 20, the outside cylindrical surface of which is provided witha sawtooth shaped groove extending around its entire periphery. For goodbalance, this sawtooth groove in the periphery of cylindrical portion ofthe valve body 20 should have at least three peaks, and it will beassumed in this case that there are three peaks, although otherembodiments may employ a larger number. In this case, three pins 22,integral with the knob 21 extend into the groove from positions evenlyspaced around the interior cylindrical surface of the knob. Each peak isprovided with a leaf spring 24.

As the knob 21 is rotated manually, each of the three pins 22, integralwith the knob, moves up the inclined helical groove from the lowestpoint 23 b to the peak 23 a, thereby pulling, via the swivel link 6, thediaphragm 4 away from its seat, thereby opening the flow passage. Uponreaching the peak each of the pins 22 will come into contact with aspring 24. If there is sufficient suction force, produced when there ismilk flowing past the left-hand (as seen in FIG. 4) side of thediaphragm, then each spring 24 will be held depressed in its positionshown in FIG. 5(b), and the valve will be held in its open position. Ifthe suction force is insufficient, due to only air flowing through thevalve for example, then each spring 24 will push its pin 22 forward asshown in FIG. 5(a) to the straight drop portion of the groove, whereuponthe air suction in the system will pull the diaphragm, and with it thelink 6 and the knob 21 with its pins 22 down once again to the positionshown in FIG. 4 (advanced ⅓ of a turn).

The valve may of course also be closed manually by turning the rotatingthe knob very slightly from the peak position to the straight dropportion.

FIGS. 6 and 7 show purely schematically the open and closed positionsrespectively of an embodiment of the invention similar to that describedin connection with FIGS. 2 and 3 but without any biasing spring.Corresponding components have been given the same reference numerals asin FIGS. 2 and 3. This valve is intended for manual operation withoutthe automatic closing feature of the speing biased valves describedabove.

FIG. 8 shows in a similar manner an embodiment, in its closed position,intended for manual operation corresponding to that described inconnection with FIG. 4, but where the biasing spring has been eliminatedand corresponding components have received the same reference numeralsas in FIG. 4.

It will be understood that although this description refers to “peaks”,“straight drop”, “lowest point” etc., this vertical reference is onlyfor ease in following the description of the drawings and that in actualuse the valve, when incorporated into a milk claw and a cluster, will infact be upside-down or turned 90° relative to what is shown in thefigures. The valve responds to vacuum and not gravity.

In addition to the two embodiments described above of the valveaccording to the invention, many other valve designs within the scope ofthe claims are also possible, for example instead of a lever or a knob,a design using a link-connected cam with a top dead-center point, whichis stable only when there is sufficient milk flow through the valve willfall within the scope of the invention.

It will also be readily obvious to the person skilled in the art thatthe above described valves may be provided with various types of manuallocks to keep them in open position regardless of pressure and liquidflow, for the purpose of flushing and cleaning the system.

What is claimed is:
 1. Valve for shutting off and turning onsuction-induced flow from a teatcup or teatcups in a milking machine,said valve including: a valve body (1) having at least one inlet (2) formilk flow from a teatcup and an outlet for milk flow from said valve, aswell as a valve seat, characterized by a. a diaphragm mounted in saidvalve body (1) said diaphragm (4) being movable between an open positionpermitting flow from said inlet(s) to said outlet, and a closed positionsealing against said valve seat, cutting off flow between said inlet(s)(2) and said outlet, b. a manual actuator (5) mounted in or on saidvalve body (1) to swing or rotate between at least first and secondpositions, c. a non-extendible link (6) connected between said manualactuator and a point on said diaphragm (4); the diaphragm (4) being heldin its open position by means of said link (6) when said manual actuatoris in its first position; the diaphragm being released to allow it toassume its closed position, when said manual actuator is moved to itssecond position; said diaphragm, when in its open position, exerting viathe link (6) a force on the manual actuator (5), urging it towards itsfirst position.
 2. Valve according to claim 1, characterized in thatsaid manual actuator a lever (5) pivotally mounted in said valve body(1) to pivot between a first end position and a second end position,said link (6) extending between a point on said lever (5) remote fromthe pivot point of said lever (5) to a point on said diaphragm (4), thediaphragm (4) being held in its open position by means of said link (6)when said lever is in its first end position, the diaphragm beingreleased to allow it to assume its closed position, when said lever ismoved to its second end position.
 3. Valve according to claim 1,characterized in that said manual actuator is a knob (21) which isrotatably mounted on said valve body (20), and which, when rotatedmanually, can be moved, supported on a helical surface or helicalsurfaces of the valve body, from said second position (23 b) to saidfirst, diaphragm-open, position; continued rotation from said firstposition allowing the knob to return precipitously to said seconddiaphragm-released position.
 4. Valve according to claim 3,characterized by a plurality of evenly circumferentially spaced helicalsurfaces each leading to a first diaphragm-open position followed by aprecipitous portion defining a second diaphragm-release position, saidknob being supported on all of said plurality of helical surfacessimultaneously.
 5. Valve according claim 4, characterized in that saidhelical surfaces are comprised in grooves (23) and that the knob (21) ishollow and is supported via inward projections (22) from the interior ofthe knob extending into said grooves.
 6. Valve according claim 3,characterized in that said helical surfaces are comprised in grooves(23) and that the knob (21) is hollow and is supported via inwardprojections (22) from the interior of the knob extending into saidgrooves.
 7. Valve according to claim 1, characterized in that saidmanual actuator is biased towards its second position; said diaphragm,when in its open position, exerting via the link (6) an opposing forceon the manual actuator (5), urging it towards its first position; saidopposing force, when there is a predetermined suction which inducesliquid flow through the valve body, overcoming the biasing force urgingthe actuator towards its second position; said opposing force notovercoming the biasing force when there is a drop below saidpredetermined suction for the liquid flow through the valve.
 8. Valveaccording to claim 7, characterized in that said manual actuator is alever (5) pivotally mounted in said valve body (1) to pivot between afirst end position and a second end position, said lever being spring(7) biased towards its second end position, said link (6) extendingbetween a point on said lever (5) remote from the pivot point of saidlever (5) to a point on said diaphragm (4), the diaphragm (4) being heldin its open position by means of said link (6) when said lever is in itsfirst end position, the diaphragm being released to allow it to assumeits closed position, when said lever is moved to its second endposition, said diaphragm, when in its open position, exerting via thelink (6) an opposing force on the lever (5), urging it towards its firstend position, said opposing force, when there is a predetermined suctionwhich induces liquid flow through the valve body, overcoming the springbiasing force urging the lever towards its second end position, saidopposing force not overcoming the spring biasing force when there is adrop in the suction for the liquid flow through the valve.
 9. Valveaccording to claim 7, characterized in that said manual actuator is aknob (21) which is rotatably mounted on said valve body (20), and which,when rotated manually, can be moved, supported on a helical surface orsurfaces of the valve body, from said second position (23 b) to saidfirst, diaphragm-open, position; said rotary knob, when in its firstposition, being spring-biased to continue automatically rotation fromsaid first position to a precipitous portion or portions allowing it toreturn to said second diaphragm-released position unless the opposingforce, when there is a predetermined flow-inducing suction through thevalve body, overcomes the spring biasing force which urges the knob (21)towards its second position, thereby retaining the knob in its first,diaphragm-open position, unless the knob is advanced manually. 10.Milking machine claw comprising a valve as specified in claim
 1. 11.Milking system comprising a suction source, a milk receiving container(17), at least one cluster having a claw (13) as specified in claim 10,and at least two teatcups.